Internet social networks have become a compelling social phenomenon. Internet social networks allow users to, for example, maintain profiles, grant other users access to their profiles, interact with each other's profiles, post media on their profiles, and perform other actions. Users may create content or interact with content posted on the profiles of their friends within the network. In a social network, an Internet user typically builds a group of friends or followers who receive updates of the user's activity. Each instance of user activity generates a story that is visible to other users on their homepages, most notably the user's friends. For example, the action of a user posting a link to an article on his profile may generate a story. Other users, in turn, may comment on the link, click the link, or select an option indicating that they ‘like’ the link. The stories generated by a user's creation of content and his interactions with the profiles of other users summarize the user's activity on the social network.
As the volume of users of a social network grows, the number of user interactions and content items created by users increases exponentially. Social networks employ increasingly sophisticated techniques for classifying user actions and content items such that patterns in user activity may be identified. Determining these patterns enables operators of social networks to not only monetize the social networking platform through the placement of targeted advertising, but to optimize and enhance the user experience. For example, many users have a high number of friends whose activity generates upwards of hundreds of stories a day. Rather than simply displaying all of these stories in chronological order on a user's homepage, the social network may wish to selectively display only those stories with which the user is likely to interact.
As the variety of content that social networks allow their users to post and the manner in which that content is displayed evolve, the mechanisms for tracking user interactions must also evolve. For example, a story may contain a link to an article, a profile picture with an embedded link to the user's profile, and a text link to the user's profile. If one of the user's friends clicks a link to the user's profile, the social network may wish to know whether the friend clicked the profile picture or the text link. Similarly, if the friend clicks on the link to the article, the social network may wish to know whether it was clicked from within the user's profile or from the “news feed” within the friend's homepage. If the links within the story contain no information other than the uniform resource locator (“URL”) of the user's profile or the article, the social network may not know exactly which link the friend has clicked.